Greedy Algorithm and Model for Analysis of a Bus Fleet's Operations

Bus Company (BUSCO) approached Fourier-E, an industrial engineering company, to develop and optimise the Duty Master for their Sowetan operations. The Duty Master is a scheduling blue print that dictates the operations and management of a company's bus eet. Through the manipulation of positioning routes and depot allocations, a Duty Master should minimise distances travelled and eet size. In doing so, operating costs are reduced. Fourier-E had already developed their own algorithm for BUSCO's Sowetan Duty Master, which had resulted in substantial savings in the number of busses required to complete all revenue routes and total distances travelled. However, the run-time of their model of approximately 20 minutes to generate a solution is a serious limitation and prohibitive for client use. The primary aim of this project was to develop an online user-friendly model to en- able BUSCO to rapidly solve their eet scheduling requirements. Speci cally, the new algorithm had to be capable of generating a solution for the Duty Master in less than ten seconds. To accommodate the reduction in run-time, Fourier-E speci ed that the devel- oped algorithm must generate a solution which is at least 80% as good as their existing one in terms of busses saved and positioning kilometres driven. The problem of developing the Duty Master can be modelled as a Mulit-Depot Vehi- cle Routing Problem with Pickup and Delivery, Time Windows and Intermediate Facili- ties (MDVRPPDTWIF). To solve the problem, a greedy-heuristic was developed, called \Greedy-Bin". Computational tests showed that the algorithm exceeds all Fourier-E's speci cations and performs particularly well in run speed, whch at 1.23 seconds, is 976 times faster than the existing approach. The Greedy Bin algorithm performs at 88% of Fourier-E's with regards to busses saved and 96.7% for kilometres saved. The Greedy-Bin algorithm met all validation criteria. In order for clients to access the algorithm, an online user interface was developed which enables rapid evaluation of various operatonal scenarios. To achieve this, ve variables that can be manipulated by the client were added to the model, namely: bus speed, revenue routes, loading bu er, distance bu er and day and night depot capacities. Model outputs are: the number of busses needed to complete all revenue routes, positioning distance, depot allocations and eet utilisation throughout the day. Manipulation of the Duty Master model also demonstrates its capacity to save on oper- ating expenses by generating alternative solutions for depot allocations. Additionally, the nancial implications of changing bus speeds and manipiulating loading and positioning bu ers are demonstrated. Finally, in an industry where tenders for new revenue routes are highly competitive, the model can be used to assess the potential nancial implications of adding new routes and in doing so, inform the decision of whether or not to tender for those routes.Mini Dissertation (B Eng. (Industrial and Systems Engineering))--University of Pretoria, 2017

Maintaining biosecurity in aquaculture systems: A constraint or a challenge

Biosecurity can be defined as the protection of plants, animals (including humans and associated activities) and the wider environment from the unwanted impacts of biological agents including diseases and pests. As a discipline, biosecurity can be applied at various levels. In the context of aquatic animal disease, this can range from managing the health of individual animals, through whole commercial enterprise to national or international biosecurity. The last three decades or so have seen an increase in the farming of aquatic animals worldwide – a situation compounded from a biosecurity perspective by a quantum leap in aquaculture technologies, countries and species new to aquaculture, increased international movement of juvenile animals and broodstock; all in an environment of little knowledge of the health status of source populations and the frequent emergence of new diseases. The end-result of this change has been significant farm level production losses well documented in the scientific and lay literature. The focus on increased farm level biosecurity in recent times has been in direct response to this very real threat. All aquaculture operations rely on trade (commercial exchanges) to some extent. Trade provides stock, genetic material, inputs (such as feeds, vaccines, treatments, etc.) and takes the outputs (product). Aquaculture operations are not isolated from the realities of trade and the associated biosecurity risks. This paper describes the various elements that make for good farm level biosecurity and assesses the resourcing needs against net long- and short-term benefits to production. This paper also examines the role that farm biosecurity plays in overall regional or national biosecurity systems, with particular emphasis on the Australian experience. Farm level biosecurity is placed in context with inter- or intra-national disease zoning (and compartmentalisation), national quarantine control and global biosecurity initiatives such as international disease reporting and standards setting. The necessity for on-farm biosecurity as a complement to zoning and the more traditional country quarantine requirements is emphasized

Reframing social work assessment: Connecting spaces and people

This paper seeks to reframe social work assessment, reflect on complexity, autopoietic theory, narrative, and life stories, and introduces a conceptual interactive practice tool, Connecting Spaces. This tool is being designed to facilitate assessments and therapeutic work with children and vulnerable adults in person and online. Social work is concerned with systems involving people, often during crisis, their environments, and networks where engagement and assessment cannot function outside of communication between assessor and assessed. Social workers are nested within their own personal, biological, and professional networks including employing agency and professional regulatory bodies. Complexity arises because social workers must condense information into stories of what might happen and make sense how best to support people. Munro (2011) in her review of child protection explains social workers try to understand and help people and she reflects on the interplay between conscious analysis and intuition in assessment and decision making. Ten years on from Munro’s recommendations The Case for Change (Children’s Social Care Independent Review, 2021) highlights the continued need for less bureaucratic process-led practice and more direct work with children and families.Given the prominence of attachment theory in social work, it is a surprise Siegal’s Mindsight, which is the capacity to clarify, label and analyse the internal emotional world and its response to the external word, has gained little attention in social work. The potential for Mindsight’s application in social work is enhanced by narratives, storytelling and life story therapy with children and vulnerable adults. Connecting Spaces can be used to create a narrative about the person's life: past, present and/or future. The aim is to inform and improve decision making by enabling the person's understanding, views, wishes and feelings to be explored, heard, presented, evidenced, and considered. Further, it has the potential to present and consider multi-perspectives and narratives such as in family and wider systems. This flexible communication conceptual tool is designed to have a range of uses and it is intended to be provided in both digital and physical form to suit a range of needs. This tool does not aim to replace but to enhance building relationship, safety, and communication in direct work with a child or vulnerable adult

International educational tourism : does it foster global learning? A survey of South African high school learners

International educational tourism has the potential to foster global learning; however, very little empirical research exists to support this claim. This study responds to the growing demand in the literature for rigorous empirical research to test the underpinning assumption of IET. A global learning survey instrument is developed and completed by 1152 Grade 11 learners in 16 South African exclusive high schools. In doing so, this paper demonstrates that some types of IET are more conducive to global learning than others. Furthermore, for significant global learning to occur, educational tourism needs to be facilitated and cultural difference needs to be experienced. Personality traits that include curiosity, altruism, and being open-minded to new experiences, are identified as predictors of global learning, but the effect of school-based academic achievement is small. Additionally, through the synthesis of educational tourism, international education, experiential learning and global learning theories, the concept of IET is developed.University of Pretoriahttp://www.elsevier.com/locate/tourman2018-10-30hj2017Marketing ManagementTourism Managemen

A method for isolating and culturing placental cells from failed early equine pregnancies

Early pregnancy loss occurs in 6–10% of equine pregnancies making it the main cause of reproductive wastage. Despite this, reasons for the losses are known in only 16% of cases. Lack of viable conceptus material has inhibited investigations of many potential genetic and pathological causes. We present a method for isolating and culturing placental cells from failed early equine pregnancies. Trophoblast cells from 18/30 (60%) failed equine pregnancies of gestational ages 14–65 days were successfully cultured in three different media, with the greatest growth achieved for cells cultured in AmnioChrome™ Plus. Genomic DNA of a suitable quality for molecular assays was also isolated from 29/30 of these cases. This method will enable future investigations determining pathologies causing EPL

Elemental assessment of vegetation via portable X-ray fluorescence (PXRF) spectrometry

Please read abstract in the article.http://www.elsevier.com/locate/jenvman2019-03-15hj2019Plant Production and Soil Scienc

Identification and phylogenetic comparison of p53 in two distinct mussel species (Mytilus)

Author Posting. © The Authors, 2005. This is the author's version of the work. It is posted here by permission of Elsevier B. V. for personal use, not for redistribution. The definitive version was published in Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology 140 (2005): 237-250, doi:10.1016/j.cca.2005.02.011.The extent to which humans and wildlife are exposed to anthropogenic challenges is an important focus of environmental research. Potential use of p53 gene family marker(s) for aquatic environmental effects monitoring is the long-term goal of this research. The p53 gene is a tumor suppressor gene that is fundamental in cell cycle control and apoptosis. It is mutated or differentially expressed in about 50% of all human cancers and p53 family members are differentially expressed in leukemic clams. Here, we report the identification and characterization of the p53 gene in two species of Mytilus, Mytilus edulis and Mytilus trossulus, using RT-PCR with degenerate and specific primers to conserved regions of the gene. The Mytilus p53 proteins are 99.8% identical and closely related to clam (Mya) p53. In particular, the 3′ untranslated regions were examined to gain understanding of potential post-transcriptional regulatory pathways of p53 expression. We found nuclear and cytoplasmic polyadenylation elements, adenylate/uridylate-rich elements, and a K-box motif previously identified in other, unrelated genes. We also identified a new motif in the p53 3′UTR which is highly conserved across vertebrate and invertebrate species. Differences between the p53 genes of the two Mytilus species may be part of genetic determinants underlying variation in leukemia prevalence and/or development, but this requires further investigation. In conclusion, the conserved regions in these p53 paralogues may represent potential control points in gene expression. This information provides a critical first step in the evaluation of p53 expression as a potential marker for environmental assessment.AFM was supported by the Greater Vancouver Regional District, BC, Canada, and RLC was supported by STAR grant R82935901 from the Environmental Protection Agency (USA)

Our friend in the north: the origins, evolution and appeal of the cult of St Duthac of Tain in later Middle Ages

St Duthac of Tain was one of the most popular Scottish saints of the later middle ages. From the late fourteenth century until the reformation devotion to Duthac outstripped that of Andrew, Columba, Margaret and Mungo, and Duthac's shrine in Easter Ross became a regular haunt of James IV (1488-1513) and James V (1513-42). Hitherto historians have tacitly accepted the view of David McRoberts that Duthac was one of several local saints whose emergence and popularity in the fifteenth century was part of a wider self-consciously nationalist trend in Scottish religious practice. This study looks beyond the paradigm of nationalism to trace and explain the popularity of St Duthac from the shadowy origins of the cult to its heyday in the early sixteenth century

Effects of Elevated Temperature and Carbon Dioxide on the Growth and Survival of Larvae and Juveniles of Three Species of Northwest Atlantic Bivalves

Rising CO2 concentrations and water temperatures this century are likely to have transformative effects on many coastal marine organisms. Here, we compared the responses of two life history stages (larval, juvenile) of three species of calcifying bivalves (Mercenaria mercenaria, Crassostrea virginica, and Argopecten irradians) to temperatures (24 and 28°C) and CO2 concentrations (∼250, 390, and 750 ppm) representative of past, present, and future summer conditions in temperate estuaries. Results demonstrated that increases in temperature and CO2 each significantly depressed survival, development, growth, and lipid synthesis of M. mercenaria and A. irradians larvae and that the effects were additive. Juvenile M. mercenaria and A. irradians were negatively impacted by higher temperatures while C. virginica juveniles were not. C. virginica and A. irradians juveniles were negatively affected by higher CO2 concentrations, while M. mercenaria was not. Larvae were substantially more vulnerable to elevated CO2 than juvenile stages. These findings suggest that current and future increases in temperature and CO2 are likely to have negative consequences for coastal bivalve populations